CVE-2023-45128 is a critical-severity (CVSS 10) Improper Input Validation vulnerability in github.com/gofiber/fiber/v2. A fix is available for github.com/gofiber/fiber/v2 — see the affected versions and patch details below.
CSRF Token Reuse Vulnerability in fiber
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-45128.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-45128 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/gofiber/fiber/v2Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
A Cross-Site Request Forgery (CSRF) vulnerability has been identified in the application, which allows an attacker to inject arbitrary values and forge malicious requests on behalf of a user. This vulnerability can allow an attacker to inject arbitrary values without any authentication, or perform various malicious actions on behalf of an authenticated user, potentially compromising the security and integrity of the application.
Vulnerability Details
The vulnerability is caused by improper validation and enforcement of CSRF tokens within the application. The following issues were identified:
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Token Injection: For 'safe' methods, the token was extracted from the cookie and saved to storage without further validation or sanitization.
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Lack of Token Association: The CSRF token was validated against tokens in storage but not associated with a session, nor by using a Double Submit Cookie Method, allowing for token reuse.
Specific Go Packages Affected
github.com/gofiber/fiber/v2/middleware/csrf
Remediation
To remediate this vulnerability, it is recommended to take the following actions:
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Update the Application: Upgrade the application to a fixed version with a patch for the vulnerability.
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Implement Proper CSRF Protection: Review the updated documentation and ensure your application's CSRF protection mechanisms follow best practices.
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Choose CSRF Protection Method: Select the appropriate CSRF protection method based on your application's requirements, either the Double Submit Cookie method or the Synchronizer Token Pattern using sessions.
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Security Testing: Conduct a thorough security assessment, including penetration testing, to identify and address any other security vulnerabilities.
Defence-in-depth
Users should take additional security measures like captchas or Two-Factor Authentication (2FA) and set Session cookies with SameSite=Lax or SameSite=Secure, and the Secure and HttpOnly attributes.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/gofiber/fiber/v2 | all versions | 2.50.0go get github.com/gofiber/fiber/v2@v2.50.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gofiber/fiber/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/gofiber/fiber/v2 to 2.50.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-45128 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-45128 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-45128. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-45128 in your dependencies?
O3 Security finds CVE-2023-45128 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.